| We are now in a great new era of Internet. The spirit of Internet is to share information. It's the same for data of GIS (Geographic Information System). But the data in different GIS is made available in a variety of formats. It seems impossible to share geographic data between different GIS directly.In order to solve this problem, GIS need to give a solution-data source integration.There are many integration methods. Each method has its own trait. Almost every GIS product gives a solution for data source integration. The most popular product ArcGIS, published by ESRI, uses spatial extensions and a data server, to abstract different data source. GNet, another GIS product, use a component to solve different data source. But each has its limitations.This dissertation introduces an improved data source integration method to GNet. This method uses a data source module to integrate data source in different kinds. It improves the data source integration in two sides: improved functionality and improved interface.At last, in order to show how to integrate data source into GNet, this dissertation give the design and implementation for each kind of data source. These data source include file data source, memory data source, ArcSDE data source. The main task to design and implement a data source is to map a geographic data model to data model in GNet, including data representation, data organization, and data access. |
